The present invention relates to a component, preferably a turbine blade/vane, which can be subjected to hot gas. More preferably, it relates to one which has at least one duct which can be subjected to a cooling fluid and is bounded by two first walls opposite to one another. The walls are preferably provided with one or more turbulators to improve the heat transfer between the component and the cooling fluid. The turbulators of the first wall and the turbulators of the second wall preferably have the same direction of inclination and being inclined relative to a flow direction of the cooling fluid by an angle of inclination.
A component, in the embodiment as a gas turbine blade/vane, is known from EP 0 758 932 B1 or U.S. Pat. No. 5,695,321, in particular FIG. 9A. The known gas turbine blade/vane has a hollow configuration and has at least one duct, which can be subjected to a cooling fluid. By this, the inlet temperature of the gas into the gas turbine can be increased so that the efficiency is improved. The duct is bounded by two first walls opposite to one another. One or more turbulators, which improve the heat transfer between the gas turbine blade/vane and the cooling fluid, are provided on these walls. The turbulators of the two walls have the same direction of inclination and are inclined by the same angle of inclination relative to a flow direction of the cooling fluid. In such an embodiment, the duct can be locally constricted by the turbulators. This particularly occurs when the two walls located opposite to one another, and therefore the turbulators, have different lengths. Sections of the turbulators of the two walls are then located opposite to one another at the same height. At this location, the duct is locally constricted.
Because, in the usual case, each wall is provided with a plurality of turbulators, this constriction occurs repeatedly. There is not, therefore, a cooling fluid flow with an essentially constant cross section oscillating uniformly from one wall to the other. The cross section available for the cooling fluid is, rather, continuously varied so that pressure losses occur.
U.S. Pat. No. 5,413,458 shows a gas turbine guide blade with a platform. The platform is provided with a flow chamber in which turbulators are arranged in such a way that cooling fluid flowing through the flow chamber is guided to the corners of the platform.
An object of the present invention is, therefore, to provide a component which can be subjected to hot gas. Preferably, a component is provided in which an essentially uniform duct cross section is present, without local constrictions, over the complete length of the turbulators.
This object is preferably achieved, according to the invention and in a component, by the angle of inclination of the turbulators of the first wall being different from the angle of inclination of the turbulators of the second wall.
The different angles of inclination of the turbulators of the first and second walls permit an arrangement of the turbulators without local constrictions. Because of the different angles of inclination, there are no longer any sections of the turbulators opposite to one another. The turbulators of one wall can, rather, be arranged to alternate almost entirely over its complete length, with the turbulators of the other wall. This provides a uniform cross section of the duct for the cooling fluid in the direction of the length of the turbulators. The changes in cross section, and the pressure losses associated with them, occurring in the case of the known designs are essentially reduced.
Advantageous embodiments and developments of the invention are given in the subclaims.
The length of the first wall is advantageously greater than the length of the second wall. Different cross sections can, by this, be selected for the component which can be subjected to hot gas.
In an advantageous development, the first two walls have a curved configuration. By way of the curved walls, a cross section in the shape of an aerofoil section can be selected for for the component which can be subjected to hot gas. This cross section is preferred, in particular, for the application as a turbine blade/vane.
In an advantageous embodiment, the angle of inclination of the turbulators of the first wall is greater than the angle of inclination of the turbulators of the second wall. The length of the turbulators of the first wall is reduced by this, whereas the length of the turbulators of the second wall is increased. In this arrangement, the angles of inclination are selected in such a way that the turbulators on the two walls are arranged so that they alternate almost completely with one another. This leads to an essentially uniform cross section of the duct over the complete length of the turbulators.
Two further walls are advantageously provided to form boundaries for the duct, which walls connect the two first walls to one another. The internal space of the component which can be subjected to hot gas is subdivided by these two further walls into a plurality of ducts, for example three, which ducts are in connection with one another. The cooling fluid flows sequentially through the three ducts. When used as a gas turbine blade/vane, the first ductxe2x80x94in which the temperature of the cooling fluid is lowestxe2x80x94is advantageously arranged at the inlet flow end of the gas turbine blade/vane.
In an advantageous development, the two further walls are arranged at an angle relative to one another. This angular arrangement permits an alignment of these further walls essentially at right angles to the two first walls. This alignment leads to an optimized guidance of the cooling fluid. The angled location of the two further walls is, furthermore, more suitable for accepting loads in the application as a gas turbine blade/vane.
In a first advantageous embodiment, the turbulators preferably have a straight configuration. This straight configuration facilitates removal from the mold of the component according to the invention and makes the manufacturing process cheaper.
In a further advantageous embodiment, the turbulators preferably have a curved configuration. Curved turbulators permit complete alternation of the turbulators over their entire length. The pressure losses due to changes in cross section are minimized to the greatest extent possible.